In a standard portable spectrophotometer, the incident light is generally, but not always, set at an angle of forty-five (45) degrees from normal. The resulting spectral reflectances that can be gathered are generally in the same plane as the incident light and are on either side of the specular angle (the equal and opposite angle to the incident light) as well as nearer to the incident light source itself.
New portable spectrophotometric devices offer a vast multitude of angular color response (spectral reflectance) data. Besides the addition of several new angles, including azimuthal, or out-of-plane angles, many instruments also offer additional light sources with different geometries. By way of example, the incident light source of a second illuminator may be located at fifteen (15) degrees from normal. The plurality of combinations of incident light and angular response can provide both too little information and too much information regarding the target coating.
Thus, there is a need for systems and methods that can be used to evaluate all of the data, including specific combinations of data, obtained from a spectrophotometer by using multi-dimensional geometrical evaluation and calculations.